As the nation copes with increasing numbers of obese Americans, United Airlines has joined the list of air carriers making overweight passengers pay more to fly.
As of Wednesday, passengers too large to fit comfortably in a coach seat may be required to buy a second ticket or upgrade to business class, where seats are larger -- if United's flight attendants can't find two open seats for them.
The carrier, whose parent company is Chicago-based UAL Corp., said it decided to adopt the tougher policy after receiving more than 700 complaints last year from passengers "who did not have a comfortable flight because the person next to them infringed on their seat," spokeswoman Robin Urbanski said.
How to accommodate severely overweight passengers is an issue that has long rankled air travelers. Issues of weight and seat proximity have become more sensitive in recent years as airlines narrow seat widths and flights have become fuller.
But as airlines adopt or toughen policies for obese passengers, some question how they can enforce such measures fairly.
"How do you eyeball someone and decide they're not going to fit?" said aviation consultant Robert Mann, president of R.W. Mann & Co. "From a knees-to-seat-back perspective, I don't fit. I'm 6 feet, 4 inches.
"It's reached the point where it's essentially impossible to sit in coach and have the person in front of you recline."
Southwest Airlines requires passengers who can't comfortably lower their armrests to purchase tickets for two adjacent seats. Southwest will refund the cost of the second seat if a flight isn't sold out.
Although the policy has been on Southwest Airlines Co.'s books for a quarter of a century, the low-fare carrier faced a backlash when it reminded consumers of its standards for larger passengers in 2002, as Southwest switched from plastic boarding cards to electronic tickets.
Southwest still gets plenty of mail on the issue, spokeswoman Brandy King said. But the upset customers are likelier to be passengers who believe they didn't have enough room on a flight.
United's flight attendants, who will have the delicate task of enforcing the new policy, have traditionally sought to accommodate, free of charge, passengers who spill over their seats. That hasn't changed.
"We'll first try to re-accommodate you on another seat on the flight," Urbanski said. "If the flight is full, and that's not often the case these days, you'll be bumped from the flight." If this occurs, passengers will be forced to find a flight with open seating, buy two seats or pay for an upgrade to a class of service with wide seats.
United, the nation's third-largest carrier, said it would waive fees normally charged for changing travel plans. If seating is not available and a passenger decides not to travel, the ticket will be refunded without any penalty, even if it is a nonrefundable ticket.